This invention relates to an improved oxygen-containing tungsten compound on an alumina catalyst useful for production of oximes by selective oxidation, in the vapor phase, of primary aliphatic and alicyclic amines such as cyclohexylamine with elemental oxygen gas. More particularly, this invenion relates to an improved oxygen-containing tungsten on an alumina catalyst and method of making, regenerating and using same for selective vapor phase oxidation of saturated primary aliphatic and alicyclic amines such as cyclohexylamine by elemental oxygen to the corresponding oxime.
U.S. Pat. No. 4,337,358 (J. N. Armor) discloses a process for oxidizing primary saturated aliphatic and alicyclic amines having 2 to 12 carbon atoms by elemental oxygen to oximes, especially cyclohexylamine to cyclohexanone oxime, in a vapor phase using a silica gel catalyst, and using temperatures between about 120.degree. C. and 250.degree. C. at atmospheric pressure.
Co-pending U.S. patent application Ser. No. 451,702, filed Dec. 20, 1982, now U.S. Pat. No. 4,504,681 discloses a process for production of oximes by contacting, in the vapor phase, saturated primary aliphatic or alicyclic amines of 2 to 12 carbons with elemental oxygen-containing gas in the presence of an effective amount of a catalyst comprising alumina or oxygen-containing tungsten substance on a metal oxide support such as .gamma.-alumina.
A Japanese Patent Publication No. SHO47-25324, of July 11, 1972, relates to oxidation in the liquid phase, of primary aliphatic and alicyclic amines wherein a tertiary alcohol is present and preferably ammonia gas is present. A catalyst such as tungstic acid, phosphotungstic acid, molybdic acid, selenic acid, or selenious acid is preferably used. Highest conversions obtained in the examples are less than 20% and yields based on oxygen consumed are less than 50%.
U.S. Pat. No. 2,706,204 (K. Kahr) discloses that oximes are obtained by treating a primary amine, in the liquid phase, with hydrogen peroxide in the presence of a salt of an acid of tungsten, molybdenum or uranium as a catalyst.
In catalytic systems, the catalysts eventually lose sufficient activity that it is no longer desirable to continue processing the feed, and thus regeneration and reactivation of the catalyst are necessary to restore the catalyst to its initial activity. In some catalytic systems, regeneration and reactivation are accomplished by taking all reactors off processing to perform the necessary regeneration and reactivation. In swing-type reactor systems, the regeneration and reactivation can be done on an individual reactor basis. In some cases, regeneration and reactivation may require removal of the catalyst from the reactor.